Solenoid operated spray apparatus



July 19, 1960 H. A. BALL SOLENOID OPERATED SPRAY APPARATUS Filed 001;.21, 1955 ATTORNEY United States Patent O SOLENOID OPERATED SPRAYAPPARATUS Henry A. Ball, Glenshaw, Pa., assignor to The CleanolaCompany, Glenshaw, Pa., a corporation of Pennsylvania Filed Oct. 21,1955, Ser. No. 541,988

4 Claims. (Cl. 239-583) This invention pertains to coating apparatus forapplying coatings to objects. More particularly this invention relatesto mechanically controlled-apparatus for applying thin film-formingcoating composition attenuated by a volatile carrying liquid to objectswithout the use of air.

The apparatus in prior use for applying coatings to objects havefundamentally comprised a spray orifice to which the flow of coatingmaterial was controlled by a valve placed either proximate to or remotefrom the said orifice. Under conditions where the said valve was remotefrom the said orifice, a quantity of the coating composition whichremained in the system between the valve and the orifice, when the valvewas closed, was lost and often caused troublesome restricting of thesystem. In all instances the valve was operated by a stem or rod whichpassed through packing and extended outside the structure of theapparatus and, upon repeated use of the valve, the resultant Wear on thecomponent parts and deterioration of the packing permitted leakage ofthe coating composition from the system around the said stem or rod.

Therefore, one object of this invention is to provide an apparatus forapplying a thin uniform coating to objects in which none of the movingelements extends outside the structure of the said apparatus. A furtherobject of this invention is to eliminate the difliculty of residualcoating composition restricting or plugging the system. A furappear fromthe following description and the appended claims.

Briefly to describe the primary features of a coating apparatusembodying my invention, I provide a housing having an inlet for coatingcomposition connecting with a chamber within the said housing; ashut-oil valve seat within the said chamber which cooperates withmechanical means to interrupt the discharge of coating composition; anozzle communicating with the said shut-oil valve seat; and an outletfor the coating composition communicating with the said chamber topermit the continuous circulation and reheating of the said coatingcomposition. The restricted condition of the orifice of the said nozzleis such that when the attenuated coating composition is projectedtherefrom under the influence of heat-reduced viscosity and mechanicalpressure it is resolved by the abrupt release of the said pressure intothe condition of a propelled free cloud. The valve operating mechanismis an encased solenoid having as its sildable core a valve stem and isthreaded into a receptacle in the housing thereby completely enclosingthe valve so that no element of the said valve extends outside thestructure of the coating apparatus. Upon assembly of the component partsof said valve stem engages the said valve seat and can be withdrawntherefrom by actuation ofthe said solenoid. Relative-movement betweenthe object to be "ice coated and the said coating apparatus causes thesaid object to intersect the propelled free cloud of coating compositionand the film-forming content thereof adheres to the said object.

Fig. I is an elevational view of my coating apparatus.

Fig. II is a cross-sectional view through my coating apparatus taken inthe plane of section line IIII of Fig. I.

Referring to the drawings, the numeral 1 indicates an inlet for thecoating composition from the supply system (not shown) into the chamber2. A shut-oil valve seat 3 is mounted within the said chamber 2 andcommunicates with the nozzle 4 to conduct the coating compositionthereto when the coating apparatus is in operation. The said valve seat3 cooperates with the valve stem 9 which is the slidable core of thesolenoid mechanical means 5, shown in Fig. II, for which a threadedreceptacle is provided in the said housing, to interrupt the flow ofcoating composition to the said nozzle 4. A helical spring 10 engagesthe valve stem 9 and firmly compresses the valve stem 9 against thevalve seat 3 when the solenoid 5 is not actuated. Actuation of thesolenoid 5 by the switch control 11 withdraws the valve stem 9 from thevalve seat 3. An outlet 6 communicates'with the said chamber 2 toconduct the coating composition back into the supply system forreheating. A threaded receptacle 7 in the body of the housing affords anengagement for a mounting rod or handle (not shown) for the coatingapparatus. A straining screen 8 is inserted into the nozzle body toprevent clogging of the nozzle orifice which may result from solidforeign matter occurring in the coating composition.

An important feature of the novelty of my invention is found in thearrangement of the structure comprising a shut-off valve in closeproximity to the nozzle and having all of its component parts entirelyenclosed within the structure. This arrangement permits the interruptionof the coating operation without allowing the run out of any. liquidcoating composition and at the same time permits the continuedcirculation of the coating composition through the coating apparatus andthe supply system for the immediate resumption of operation, and alsoprevents any leakage of the liquid coating composition which mightotherwise result from wear on the valve stem or rod, or deteriorationoff packing.

An additional important feature is found in the versatility oftheapparatus comprising a shut-off valve operated by mechanical means ofthe solenoid type which may be controlled from a remote position eventhough the said valve is proximate to the said nozzle. The use offlexible conduit for the supply and return system facilitates mobilityof the coating apparatus and allows practically unlimited extension fromthe source of supply. This arrangement permits the insertion of thecoating apparatus embodying my invention into places and objectsinaccessible to apparatus in prior use in the art. Also a plurality ofthe apparatuses embodying my invention may be mounted in series on thesame supply system and be controlled either separately or in unison.

The coating composition contemplated for the proper functioning of mycoating apparatus comprises a filmforming material attenuated by avolatile carrying liquid which is introduced from the supply system intothe coating apparatus at a temperature of from to 200 F. and undermechanical pressure of from 300 to 500 pounds per square inch. Thenozzle orifice is restricted in size so that in an order of heat-reducedviscosity and abrupt release of the mechanical pressure at the exteriorterminus of the said orifice the coating composition is resolved intothe condition of a propelled free cloud thereby liberating a proportionof the volatile liquid comprised in the said coating composition duringpassage to the object being 3 coated (not shown) while adhering to thesaid object the film-forming material which hardens and becomes heatstable upon application.

I have operated the apparatus embodying my invention successfully byapplying a mechanical pressure of 400 pounds per square inch to theattenuated coating composition which was heated to 180 F. Under theseconditions the coating composition was resolved into a finely dispersedfree cloud upon issuance from the nozzle having an orifice .011 inch indiameter and no condensation of the coating composition into liquiddroplets during passage from the nozzle to the object being coated wasobservable. When a relative movement of 300 feet per minute was eifectedbetween my coating apparatus and the object being coated, the resultantwet coating on the said object so intersecting the propelled free cloudof coating composition was .001 inch thick which produced a uniform drycoating .00045 inch thick and the flow thereof was negligible.

To determine the quantitative disposition of the coating compositionaccomplished by the apparatus embodying my invention, operations wereconducted using a coating composition comprising 50 percentum offilm-forming solid material and 50 percentum of volatile carrying liquidby weight, the film-forming solid material comprising drying oils, dryercatalysts and resins and the volatile carrying liquid comprisingnaphtha. The coating composition so constituted was presented to mycoating apparatus at a temperature of 180 F. and under mechanicalpressure of 400 pounds per square inch and was projected from the nozzlethereof into a container which was immediately sealed. Subsequentanalysis of the material collected in the said container determined thatit was comprised 55 percentum of film-forming solid material and 45percentum of volatile carrying liquid by weight, from which it isconcluded that, in actual productive operation of my coating apparatus,the liberation of a similar proportion of the volatile carrying liquidcomprised in the coating composition will occur during passage from thenozzle to the object being coated.

Variations of the pressure, temperature, speed of relative movement, andconstituency of the coating composition may be made to effect a widerange of desired coating results. The thin uniform coatings which thepractice of these variations enables my coating apparatus to producerange from .0003 inch to .025 inch in thickness in the dry state.

Certain changes may be made in the arrangement set forth in thespecification and shown in the drawings, it being understood thatmodifications in the precise embodiment of the invention may be madewithin the scope of the following claims without departing from thespirit of the invention.

I claim as my invention:

1. In a high pressure airless spray device for applying a thin film ofcoating material to an object, a housing having interior walls defininga chamber therein and having an inlet for coating material extendingthrough one of said walls, a valve member engaging said housing andprojecting into said chamber, said valve member having a seat spacedfrom one of said walls and having a central passage extendingtherethrough, said valve memher being formed of rigid unyieldingmaterial, a spray nozzle member mounted in said housing extendingoutwardly therefrom and having a passage communicating with said passagein said valve member and having an orifice so restricted that underpressure delivery of the said coating material therefrom issuance tendsto resolve the said coating material into the condition of a propelledfree cloud, a spring loaded valve stem projecting into said chamber andhaving a resilient portion cooperating with the said valve seat to causesaid valve stem to engage said seat to interrupt the flow of coatingmaterial therethrough, and mechanical operative means for actuating saidvalve stem away from said seat, said means engaging the said housing andcooperating therewith to entirely enclose the component parts of thesaid valve.

2. A high pressure airless spray device as set forth in claim 1, whereinsaid housing is provided with an outlet for coating material, wherebycontinued circulation and conditioning of the coating material may beobtained.

3. A high pressure airless spray as set forth in claim 1, wherein asolenoid slidably engages said valve stem as its core.

4. A high pressure airless spray as set forth in claim 1, wherein theseat of said valve member is flat, and wherein the valve seat engagingportion of said valve stem is flat and extends in a plane parallel tothe plane in which said valve seat extends.

References Cited in the file of this patent UNITED STATES PATENTS1,060,089 Higgins Apr. 29, 1913 1,888,684 Middleton Nov. 22, 19322,239,987 Bramsen Apr. 29, 1941 2,619,116 Ralston Nov. 25, 19522,681,829 Wahlin June 22, 1954 2,705,663 Gilbreath Apr. 5, 19552,745,625 Booth May 15, 1956 2,805,689 De Groat Sept. 10, 1957 FOREIGNPATENTS 484,607 Canada July 8, 1952

